week 9-elle Flashcards
(95 cards)
what percent of total global oxygen is produced by marine autotrophs
50-80%
what is primary productivity
rate at which organisms store energy through the formation of organic matter (carbon-based cmpds) from inorganic carbon (CO2)
Photosynthesis
-completed by photo autotrophs
-process by which photoautotrophic organisms (primary producers) use the energy from sunlight to produce glucose from CO2 and Water
light is absorbed by
clorophyll
clorophyll
-converts light energy ti chemical energy (sugar)
-found within the thylakoids that exist within chloroplasts
Full process of photosynthesis combines 2 parts:
- Light absorption phase
- Dark reaction phase
Light absorption phase
-chlorophyll absorbs light, transfers energy to electron acceptors: ADP/NADP+
-these are transformed into ATP/NADH
Dark reaction phase
-The calvin cycle (occurs in stroma - intracellular fluid)
-enzymatically controlled
-converts energy within ATP and NADPH (combined with CO2) to glucose
Three phases of the calvin cycle
- Carbon fixation
- Reduction
- Regeneration
Carbon fixation
CO2 combined into 5 carbon chain, resulting in unstable 6 carbon cmpd immediately splitting into 2 (PGA) molecules
Reduction
PGA molecueles are phosphorylated by ATP and reduced by NADPH to form G3P
**this stage consumes ATP and NADH to make glucose
Regeneration
some G3P are used to regenerate RuBP used in phase 1 with the help of ATP
Photosynthesis in temperate regions
annual cycle of marine productivity
-blooms of phytoplankton in spring & fall
-sunlight greatest in summer
-zooplankton spike in spring
sunlight, water and seasons
sunlight reflected most in winter, least in summer
when is there most nutrient poor water
Summer
when is there a developing thermocline
spring
when is there a strong thermocline
summer
when is there a weakening thermocline
fall
when is phytoplankton and zooplankton most abundant
spring
How do primary producers make food
use energy release by inorganic chemical rxns
Aphotic zone
no light here
where are hydrothermal vent communities found
deep ocean
where do primary producers typically live
as symbionts in macro-fauna in hydrothermal vent ecosystems
EXAMPLES OF PRIMARY PRODUCERS
- giant tubeworms
-Bathymodiolus mussels
-Alviniconcha gastropods